Such angle-measurement systems are used for measuring rotary motions and rotational positions of a machine part, e.g., a shaft. The rotary motion is determined either incrementally or absolutely. The output measured value is, for example, a sequence of counting pulses, a counter value or a code word. Corresponding angle-measurement systems are used particularly in so-called pick-and-place machines in the manufacture of electronic components, or in machine tools for the measuring of rotary motions. The reproducibility or repeatability of the rotational angles of machine parts precisely to only a few angular seconds is very important when working with pick-and-place machines, for example. In particular the absolute accuracy of the measuring results of an angle-measurement system is crucial in the case of machine tools. Conventional angle-measurement systems have their own bearing assemblies for the components that are rotatable relative to one another.
The accuracy of an angle measurement is basically influenced by the quality of the angle scaling, its eccentricity, and by the radial eccentricities of the bearing assembly or by wobble errors.
German Published Patent Application No. 30 36 005 describes a method for producing an angle scaling for an angle-measurement system, in which code tracks are applied on a code disk with the aid of a laser beam. The code disk is already connected to a shaft during the writing so that the code disk is already centered relative to the shaft when the code pattern is written.
This method has the disadvantage that the angle-measurement systems produced thereby do not achieve the highest accuracies, are not sufficiently robust for many applications and, in addition, require relatively much space.